Small trampoline-type devices for physical exercise, commonly referred to as “rebounders,” typically have a frame that is circular, but may have a frame that is square, rectangular, oval, or of any number of various shapes. Such devices have a relatively small diameter of about 54 inches or less for a circular frame with the frame encompassing an area of about 2,300 square inches or less. Larger trampolines of a diameter of 60 inches or less sometimes are used for rebounding exercises. But a frame of 54 inches or less will be the more common usage. Such devices have a relatively small diameter surface area available for jumping of about 1,200 square inches or less, but could be 2,000 square inches or about equal to the frame area by using an atypical rebounder design. An example of a common rebounder device is shown in U.S. Pat. No. 7,094,181. The instant invention is particularly well suited for a trampoline large enough for a single adult sized user generally weighing less than 375 lbs.
Such devices, like larger trampolines, have a bed that is made of flexible fabric attached to a frame by spring elements such as elastic cords or coil springs. Legs support the frame at a distance above the ground. The trampoline may be square, rectangular, circular or oval, or any number of various polygonal or other shapes. The frame may be made of one of several materials, such as metals like steel, aluminum, or other alloy; or, molded plastics, composite, or other similar materials. Disclosed herein are trampoline-type devices that are large enough to support a single user, but not large enough to safely or functionally support two adult users. The device includes a perimeter frame that extends generally in a horizontal plane during use for exercising. The perimeter frame is supported above a floor surface by plural legs or other generally vertically extending structure.
Disclosed herein is a new hinge arrangement wherein a molded hinge component permits the device to be folded for easier transport or storage of the trampoline. Described is an innovative over-molded hinge unit to connect rail segments of a foldable trampoline. The over-molded hinge can be made of various materials such as cast metal, which is still unique when compared to current methods. However, for foldable trampolines, plastic or similar material is preferred for the hinge unit. Prior systems do not use the method of over-molding and completely surrounding the rail of the trampoline frame in such a manner as to allow the hinge to be installed on the rail ends without the need of a pin-like fastener or weld to hold the hinge in place on the frame, when stationary, or when it is being folded and unfolded.
A hinge device is shown which creates increased pressure and friction so that the hinge is much stronger than prior hinges and less likely to slip or move once engaged. This is the case even though the hinge device and its parts are not part of the metal frame sections, but connected after the rail of the rebounder or mini-trampoline has been fabricated. Additionally, the described connection is accomplished without the current and previous designs which require welding the metal hinge segments as an integrated part of the rail portions in order to connect them for a foldable trampoline. Traditional hinge designs are a result of the belief that welding metal and parts together was the only viable and cost effective way to ensure a hinge capable of withstanding the relatively extreme vertical forces that are exerted on a trampoline supported by a horizontally disposed hinge at a break between frame sections.
Also disclosed are several versions of the presently described hinge device, including, but not limited to, various plug frame devices that substantially increase the hinge's ability to withstand the severe stresses and force placed on this hinge when a full sized adult is jumping on the foldable trampoline device.